Rice, Henry J.

Abstract [en]

The majority of research on jet noise has considered isolated shear-flows and, as such, jet noise models based on Lighthill's acoustic analogy traditionally assume a free-space Green's function for propagation. In order to evaluate the reduction in jet noise attainable from proposed airframe shielding configurations, a jet noise model based on Lighthill's analogy is derived in this paper, which retains an explicit Green's function in the expression for the far-field spectral density. This Green's function may be evaluated to include the diffraction of the sound field about an acoustic shield. A preliminary comparison is made with the limited data available for shielded jets. In addition to facilitating the study of shielding configurations, isolated predictions made using this model compare favourably with isolated jet noise data.